The parietal cortex has been shown to be involved in a large variety of cognitive processes including attention, visual short-term memory (VSTM), object identification and individuation, number processing, and motor planning. However, it remains unclear what relationship, if any, exists between these cognitive processes, as they have generally only been compared between subjects using group-averaged analyses, which [prevents] precise analysis of the degree of co-localization within individual subjects. [The finding that] IPS contains between five and seven retinotopically defined subregions [suggests that location based processing may serve as a foundation for understanding the role of the parietal cortex across a variety of cognitive domains. Meanwhile, recent research has also implicated parietal cortex in feature based processing. Because location and feature based encoding are building blocks for all of visual cognition, understanding the role of IPS in these processes could elucidate the underlying functional organization of this region.] Thus, this project will investigate the role of retinotopic IPS regions, along with other regions within IPS, n location and feature based encoding. [Aim 1 will examine the dissociations that may exist between location and feature based encoding in different IPS subregions. Aim 2 will examine how location and feature based encoding may work in synergy to support feature integration and how different IPS subregions may contribute to this process. Both functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) techniques will be employed. By taking advantage of two cutting edge brain research methods (fMRI and TMS), the proposed work will not only provide a more complete picture of the role of IPS and its subregions in location and feature based processing, greatly advancing the understanding of the functional organization of the human parietal cortex, but will also establish a direct causal link between brain and behavior.] PUBLIC HEALTH RELEVANCE: This work will seek to understand the functional organization of parietal cortex, with a focus on understanding its role in location and feature based processing. Previous work has implicated parietal cortex in a variety of disorders involving feature and location based encoding and processing, including Hemispatial Neglect and Blint's syndrome. While this work does not directly address these disorders, the knowledge gained here can help to further the understanding of the underlying organization and functions of the particular regions of parietal cortex involved in these disorders.